The present invention relates to a distributive coupler and, more particularly, to a distributive coupler useful with at least one set of optical fibers.
In recent years, fiber optic transmission lines made up of one or more optically conductive fibers arranged to form a flexible cable for conveying light from one location to another have come into increasing use. The applications have varied although one particularly significant application has been conveying data from one location to another by modulating a light source with data to be transmitted at one end of the cable and recovering the data at the other end of the cable by a photosensitive detector. Since the data is conveyed by a medium not subject to radio frequency interference or detection, fiber optic transmission lines are particularly well adapted for applications requiring a high degree of security like those found in the data processing field.
With the increasing use of fiber optic transmission lines, the need developed for connectors capable of joining segments of cables with minimum detriment to the optical transmission path. It has been found that precise axial, angular and lateral alignment between a pair of fiber optic cables can be achieved by terminating the optical fibers of the cables in connector pin assemblies in such a way as to provide concentric alignment with respect to the outer dimensions of the connector pins. When a pair of connector pins are concentrically and accurately aligned, the ultimate result is that the optical fibers will likewise be axially, angularly and laterally aligned for efficient light transfer.
While the connector art is still developing, connector pin assemblies are available today for terminating the optical fibers of the cables so that they are concentrically and accurately aligned within accepted tolerances. More recently, there has been a growing interest in, and recognition of the need for, developing suitable distributive couplers for distributing light among fiber optic transmission lines so that one or two way communication is possible from any one or more optical fibers of a set of optical fibers to all of the optical fibers of the same or a different set of optical fibers. This interest has been spawned primarily by the need to distribute an optical signal to a plurality of locations. More particularly, distributive couplers have been sought which operate in the manner described while producing substantially uniform illumination of an entire set of optical fibers utilizing the light transmitted through any one or more optical fibers without excessive loss of light or excessive distortion of light signal pulses. Additionally, a distributive coupler has been needed to make it possible to easily adjust the optical components for use with different types of optical fibers and different pluralities of optical fibers in a manner capable of fabrication at reasonable cost and to acceptable tolerances.